xref: /linux/arch/sh/kernel/cpu/clock.c (revision d97432f1014c73bbace9eb1e67742c1bcab0c3cd) 
1 /*
2  * arch/sh/kernel/cpu/clock.c - SuperH clock framework
3  *
4  *  Copyright (C) 2005 - 2009  Paul Mundt
5  *
6  * This clock framework is derived from the OMAP version by:
7  *
8  *	Copyright (C) 2004 - 2008 Nokia Corporation
9  *	Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
10  *
11  *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
12  *
13  * This file is subject to the terms and conditions of the GNU General Public
14  * License.  See the file "COPYING" in the main directory of this archive
15  * for more details.
16  */
17 #include <linux/kernel.h>
18 #include <linux/init.h>
19 #include <linux/module.h>
20 #include <linux/mutex.h>
21 #include <linux/list.h>
22 #include <linux/kobject.h>
23 #include <linux/sysdev.h>
24 #include <linux/seq_file.h>
25 #include <linux/err.h>
26 #include <linux/platform_device.h>
27 #include <linux/debugfs.h>
28 #include <linux/cpufreq.h>
29 #include <linux/clk.h>
30 #include <asm/clock.h>
31 #include <asm/machvec.h>
32 
33 static LIST_HEAD(clock_list);
34 static DEFINE_SPINLOCK(clock_lock);
35 static DEFINE_MUTEX(clock_list_sem);
36 
37 void clk_rate_table_build(struct clk *clk,
38 			  struct cpufreq_frequency_table *freq_table,
39 			  int nr_freqs,
40 			  struct clk_div_mult_table *src_table,
41 			  unsigned long *bitmap)
42 {
43 	unsigned long mult, div;
44 	unsigned long freq;
45 	int i;
46 
47 	for (i = 0; i < nr_freqs; i++) {
48 		div = 1;
49 		mult = 1;
50 
51 		if (src_table->divisors && i < src_table->nr_divisors)
52 			div = src_table->divisors[i];
53 
54 		if (src_table->multipliers && i < src_table->nr_multipliers)
55 			mult = src_table->multipliers[i];
56 
57 		if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
58 			freq = CPUFREQ_ENTRY_INVALID;
59 		else
60 			freq = clk->parent->rate * mult / div;
61 
62 		freq_table[i].index = i;
63 		freq_table[i].frequency = freq;
64 	}
65 
66 	/* Termination entry */
67 	freq_table[i].index = i;
68 	freq_table[i].frequency = CPUFREQ_TABLE_END;
69 }
70 
71 long clk_rate_table_round(struct clk *clk,
72 			  struct cpufreq_frequency_table *freq_table,
73 			  unsigned long rate)
74 {
75 	unsigned long rate_error, rate_error_prev = ~0UL;
76 	unsigned long rate_best_fit = rate;
77 	unsigned long highest, lowest;
78 	int i;
79 
80 	highest = lowest = 0;
81 
82 	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
83 		unsigned long freq = freq_table[i].frequency;
84 
85 		if (freq == CPUFREQ_ENTRY_INVALID)
86 			continue;
87 
88 		if (freq > highest)
89 			highest = freq;
90 		if (freq < lowest)
91 			lowest = freq;
92 
93 		rate_error = abs(freq - rate);
94 		if (rate_error < rate_error_prev) {
95 			rate_best_fit = freq;
96 			rate_error_prev = rate_error;
97 		}
98 
99 		if (rate_error == 0)
100 			break;
101 	}
102 
103 	if (rate >= highest)
104 		rate_best_fit = highest;
105 	if (rate <= lowest)
106 		rate_best_fit = lowest;
107 
108 	return rate_best_fit;
109 }
110 
111 int clk_rate_table_find(struct clk *clk,
112 			struct cpufreq_frequency_table *freq_table,
113 			unsigned long rate)
114 {
115 	int i;
116 
117 	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
118 		unsigned long freq = freq_table[i].frequency;
119 
120 		if (freq == CPUFREQ_ENTRY_INVALID)
121 			continue;
122 
123 		if (freq == rate)
124 			return i;
125 	}
126 
127 	return -ENOENT;
128 }
129 
130 /* Used for clocks that always have same value as the parent clock */
131 unsigned long followparent_recalc(struct clk *clk)
132 {
133 	return clk->parent ? clk->parent->rate : 0;
134 }
135 
136 int clk_reparent(struct clk *child, struct clk *parent)
137 {
138 	list_del_init(&child->sibling);
139 	if (parent)
140 		list_add(&child->sibling, &parent->children);
141 	child->parent = parent;
142 
143 	/* now do the debugfs renaming to reattach the child
144 	   to the proper parent */
145 
146 	return 0;
147 }
148 
149 /* Propagate rate to children */
150 void propagate_rate(struct clk *tclk)
151 {
152 	struct clk *clkp;
153 
154 	list_for_each_entry(clkp, &tclk->children, sibling) {
155 		if (clkp->ops && clkp->ops->recalc)
156 			clkp->rate = clkp->ops->recalc(clkp);
157 
158 		propagate_rate(clkp);
159 	}
160 }
161 
162 static void __clk_disable(struct clk *clk)
163 {
164 	if (clk->usecount == 0) {
165 		printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
166 		       clk->name);
167 		WARN_ON(1);
168 		return;
169 	}
170 
171 	if (!(--clk->usecount)) {
172 		if (likely(clk->ops && clk->ops->disable))
173 			clk->ops->disable(clk);
174 		if (likely(clk->parent))
175 			__clk_disable(clk->parent);
176 	}
177 }
178 
179 void clk_disable(struct clk *clk)
180 {
181 	unsigned long flags;
182 
183 	if (!clk)
184 		return;
185 
186 	spin_lock_irqsave(&clock_lock, flags);
187 	__clk_disable(clk);
188 	spin_unlock_irqrestore(&clock_lock, flags);
189 }
190 EXPORT_SYMBOL_GPL(clk_disable);
191 
192 static int __clk_enable(struct clk *clk)
193 {
194 	int ret = 0;
195 
196 	if (clk->usecount++ == 0) {
197 		if (clk->parent) {
198 			ret = __clk_enable(clk->parent);
199 			if (unlikely(ret))
200 				goto err;
201 		}
202 
203 		if (clk->ops && clk->ops->enable) {
204 			ret = clk->ops->enable(clk);
205 			if (ret) {
206 				if (clk->parent)
207 					__clk_disable(clk->parent);
208 				goto err;
209 			}
210 		}
211 	}
212 
213 	return ret;
214 err:
215 	clk->usecount--;
216 	return ret;
217 }
218 
219 int clk_enable(struct clk *clk)
220 {
221 	unsigned long flags;
222 	int ret;
223 
224 	if (!clk)
225 		return -EINVAL;
226 
227 	spin_lock_irqsave(&clock_lock, flags);
228 	ret = __clk_enable(clk);
229 	spin_unlock_irqrestore(&clock_lock, flags);
230 
231 	return ret;
232 }
233 EXPORT_SYMBOL_GPL(clk_enable);
234 
235 static LIST_HEAD(root_clks);
236 
237 /**
238  * recalculate_root_clocks - recalculate and propagate all root clocks
239  *
240  * Recalculates all root clocks (clocks with no parent), which if the
241  * clock's .recalc is set correctly, should also propagate their rates.
242  * Called at init.
243  */
244 void recalculate_root_clocks(void)
245 {
246 	struct clk *clkp;
247 
248 	list_for_each_entry(clkp, &root_clks, sibling) {
249 		if (clkp->ops && clkp->ops->recalc)
250 			clkp->rate = clkp->ops->recalc(clkp);
251 		propagate_rate(clkp);
252 	}
253 }
254 
255 int clk_register(struct clk *clk)
256 {
257 	if (clk == NULL || IS_ERR(clk))
258 		return -EINVAL;
259 
260 	/*
261 	 * trap out already registered clocks
262 	 */
263 	if (clk->node.next || clk->node.prev)
264 		return 0;
265 
266 	mutex_lock(&clock_list_sem);
267 
268 	INIT_LIST_HEAD(&clk->children);
269 	clk->usecount = 0;
270 
271 	if (clk->parent)
272 		list_add(&clk->sibling, &clk->parent->children);
273 	else
274 		list_add(&clk->sibling, &root_clks);
275 
276 	list_add(&clk->node, &clock_list);
277 	if (clk->ops && clk->ops->init)
278 		clk->ops->init(clk);
279 	mutex_unlock(&clock_list_sem);
280 
281 	return 0;
282 }
283 EXPORT_SYMBOL_GPL(clk_register);
284 
285 void clk_unregister(struct clk *clk)
286 {
287 	mutex_lock(&clock_list_sem);
288 	list_del(&clk->sibling);
289 	list_del(&clk->node);
290 	mutex_unlock(&clock_list_sem);
291 }
292 EXPORT_SYMBOL_GPL(clk_unregister);
293 
294 static void clk_enable_init_clocks(void)
295 {
296 	struct clk *clkp;
297 
298 	list_for_each_entry(clkp, &clock_list, node)
299 		if (clkp->flags & CLK_ENABLE_ON_INIT)
300 			clk_enable(clkp);
301 }
302 
303 unsigned long clk_get_rate(struct clk *clk)
304 {
305 	return clk->rate;
306 }
307 EXPORT_SYMBOL_GPL(clk_get_rate);
308 
309 int clk_set_rate(struct clk *clk, unsigned long rate)
310 {
311 	return clk_set_rate_ex(clk, rate, 0);
312 }
313 EXPORT_SYMBOL_GPL(clk_set_rate);
314 
315 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
316 {
317 	int ret = -EOPNOTSUPP;
318 	unsigned long flags;
319 
320 	spin_lock_irqsave(&clock_lock, flags);
321 
322 	if (likely(clk->ops && clk->ops->set_rate)) {
323 		ret = clk->ops->set_rate(clk, rate, algo_id);
324 		if (ret != 0)
325 			goto out_unlock;
326 	} else {
327 		clk->rate = rate;
328 		ret = 0;
329 	}
330 
331 	if (clk->ops && clk->ops->recalc)
332 		clk->rate = clk->ops->recalc(clk);
333 
334 	propagate_rate(clk);
335 
336 out_unlock:
337 	spin_unlock_irqrestore(&clock_lock, flags);
338 
339 	return ret;
340 }
341 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
342 
343 int clk_set_parent(struct clk *clk, struct clk *parent)
344 {
345 	unsigned long flags;
346 	int ret = -EINVAL;
347 
348 	if (!parent || !clk)
349 		return ret;
350 	if (clk->parent == parent)
351 		return 0;
352 
353 	spin_lock_irqsave(&clock_lock, flags);
354 	if (clk->usecount == 0) {
355 		if (clk->ops->set_parent)
356 			ret = clk->ops->set_parent(clk, parent);
357 		else
358 			ret = clk_reparent(clk, parent);
359 
360 		if (ret == 0) {
361 			pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
362 				 clk->name, clk->parent->name, clk->rate);
363 			if (clk->ops->recalc)
364 				clk->rate = clk->ops->recalc(clk);
365 			propagate_rate(clk);
366 		}
367 	} else
368 		ret = -EBUSY;
369 	spin_unlock_irqrestore(&clock_lock, flags);
370 
371 	return ret;
372 }
373 EXPORT_SYMBOL_GPL(clk_set_parent);
374 
375 struct clk *clk_get_parent(struct clk *clk)
376 {
377 	return clk->parent;
378 }
379 EXPORT_SYMBOL_GPL(clk_get_parent);
380 
381 long clk_round_rate(struct clk *clk, unsigned long rate)
382 {
383 	if (likely(clk->ops && clk->ops->round_rate)) {
384 		unsigned long flags, rounded;
385 
386 		spin_lock_irqsave(&clock_lock, flags);
387 		rounded = clk->ops->round_rate(clk, rate);
388 		spin_unlock_irqrestore(&clock_lock, flags);
389 
390 		return rounded;
391 	}
392 
393 	return clk_get_rate(clk);
394 }
395 EXPORT_SYMBOL_GPL(clk_round_rate);
396 
397 /*
398  * Returns a clock. Note that we first try to use device id on the bus
399  * and clock name. If this fails, we try to use clock name only.
400  */
401 struct clk *clk_get(struct device *dev, const char *id)
402 {
403 	const char *dev_id = dev ? dev_name(dev) : NULL;
404 	struct clk *p, *clk = ERR_PTR(-ENOENT);
405 	int idno;
406 
407 	clk = clk_get_sys(dev_id, id);
408 	if (clk && !IS_ERR(clk))
409 		return clk;
410 
411 	if (dev == NULL || dev->bus != &platform_bus_type)
412 		idno = -1;
413 	else
414 		idno = to_platform_device(dev)->id;
415 
416 	mutex_lock(&clock_list_sem);
417 	list_for_each_entry(p, &clock_list, node) {
418 		if (p->name && p->id == idno &&
419 		    strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
420 			clk = p;
421 			goto found;
422 		}
423 	}
424 
425 	list_for_each_entry(p, &clock_list, node) {
426 		if (p->name &&
427 		    strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
428 			clk = p;
429 			break;
430 		}
431 	}
432 
433 found:
434 	mutex_unlock(&clock_list_sem);
435 
436 	return clk;
437 }
438 EXPORT_SYMBOL_GPL(clk_get);
439 
440 void clk_put(struct clk *clk)
441 {
442 	if (clk && !IS_ERR(clk))
443 		module_put(clk->owner);
444 }
445 EXPORT_SYMBOL_GPL(clk_put);
446 
447 #ifdef CONFIG_PM
448 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
449 {
450 	static pm_message_t prev_state;
451 	struct clk *clkp;
452 
453 	switch (state.event) {
454 	case PM_EVENT_ON:
455 		/* Resumeing from hibernation */
456 		if (prev_state.event != PM_EVENT_FREEZE)
457 			break;
458 
459 		list_for_each_entry(clkp, &clock_list, node) {
460 			if (likely(clkp->ops)) {
461 				unsigned long rate = clkp->rate;
462 
463 				if (likely(clkp->ops->set_parent))
464 					clkp->ops->set_parent(clkp,
465 						clkp->parent);
466 				if (likely(clkp->ops->set_rate))
467 					clkp->ops->set_rate(clkp,
468 						rate, NO_CHANGE);
469 				else if (likely(clkp->ops->recalc))
470 					clkp->rate = clkp->ops->recalc(clkp);
471 			}
472 		}
473 		break;
474 	case PM_EVENT_FREEZE:
475 		break;
476 	case PM_EVENT_SUSPEND:
477 		break;
478 	}
479 
480 	prev_state = state;
481 	return 0;
482 }
483 
484 static int clks_sysdev_resume(struct sys_device *dev)
485 {
486 	return clks_sysdev_suspend(dev, PMSG_ON);
487 }
488 
489 static struct sysdev_class clks_sysdev_class = {
490 	.name = "clks",
491 };
492 
493 static struct sysdev_driver clks_sysdev_driver = {
494 	.suspend = clks_sysdev_suspend,
495 	.resume = clks_sysdev_resume,
496 };
497 
498 static struct sys_device clks_sysdev_dev = {
499 	.cls = &clks_sysdev_class,
500 };
501 
502 static int __init clk_sysdev_init(void)
503 {
504 	sysdev_class_register(&clks_sysdev_class);
505 	sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
506 	sysdev_register(&clks_sysdev_dev);
507 
508 	return 0;
509 }
510 subsys_initcall(clk_sysdev_init);
511 #endif
512 
513 int __init clk_init(void)
514 {
515 	int ret;
516 
517 	ret = arch_clk_init();
518 	if (unlikely(ret)) {
519 		pr_err("%s: CPU clock registration failed.\n", __func__);
520 		return ret;
521 	}
522 
523 	if (sh_mv.mv_clk_init) {
524 		ret = sh_mv.mv_clk_init();
525 		if (unlikely(ret)) {
526 			pr_err("%s: machvec clock initialization failed.\n",
527 			       __func__);
528 			return ret;
529 		}
530 	}
531 
532 	/* Kick the child clocks.. */
533 	recalculate_root_clocks();
534 
535 	/* Enable the necessary init clocks */
536 	clk_enable_init_clocks();
537 
538 	return ret;
539 }
540 
541 /*
542  *	debugfs support to trace clock tree hierarchy and attributes
543  */
544 static struct dentry *clk_debugfs_root;
545 
546 static int clk_debugfs_register_one(struct clk *c)
547 {
548 	int err;
549 	struct dentry *d, *child, *child_tmp;
550 	struct clk *pa = c->parent;
551 	char s[255];
552 	char *p = s;
553 
554 	p += sprintf(p, "%s", c->name);
555 	if (c->id >= 0)
556 		sprintf(p, ":%d", c->id);
557 	d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
558 	if (!d)
559 		return -ENOMEM;
560 	c->dentry = d;
561 
562 	d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
563 	if (!d) {
564 		err = -ENOMEM;
565 		goto err_out;
566 	}
567 	d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
568 	if (!d) {
569 		err = -ENOMEM;
570 		goto err_out;
571 	}
572 	d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
573 	if (!d) {
574 		err = -ENOMEM;
575 		goto err_out;
576 	}
577 	return 0;
578 
579 err_out:
580 	d = c->dentry;
581 	list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
582 		debugfs_remove(child);
583 	debugfs_remove(c->dentry);
584 	return err;
585 }
586 
587 static int clk_debugfs_register(struct clk *c)
588 {
589 	int err;
590 	struct clk *pa = c->parent;
591 
592 	if (pa && !pa->dentry) {
593 		err = clk_debugfs_register(pa);
594 		if (err)
595 			return err;
596 	}
597 
598 	if (!c->dentry && c->name) {
599 		err = clk_debugfs_register_one(c);
600 		if (err)
601 			return err;
602 	}
603 	return 0;
604 }
605 
606 static int __init clk_debugfs_init(void)
607 {
608 	struct clk *c;
609 	struct dentry *d;
610 	int err;
611 
612 	d = debugfs_create_dir("clock", NULL);
613 	if (!d)
614 		return -ENOMEM;
615 	clk_debugfs_root = d;
616 
617 	list_for_each_entry(c, &clock_list, node) {
618 		err = clk_debugfs_register(c);
619 		if (err)
620 			goto err_out;
621 	}
622 	return 0;
623 err_out:
624 	debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
625 	return err;
626 }
627 late_initcall(clk_debugfs_init);
628